In general, in multi-channel audio encoding and decoding techniques, a number of channel signals of a multi-channel signal are downmixed into fewer channel signals, side information regarding the original channel signals is transmitted, and a multi-channel signal having as many channels as the original multi-channel signal is restored.
Object-based audio encoding and decoding techniques are basically similar to multi-channel audio encoding and decoding techniques in terms of downmixing several sound sources into fewer sound source signals and transmitting side information regarding the original sound sources. However, in object-based audio encoding and decoding techniques, object signals, which are basic elements (e.g., the sound of a musical instrument or a human voice) of a channel signal, are treated the same as channel signals in multi-channel audio encoding and decoding techniques and can thus be coded.
In other words, in object-based audio encoding and decoding techniques, object signals are deemed entities to be coded. In this regard, object-based audio encoding and decoding techniques are different from multi-channel audio encoding and decoding techniques in which a multi-channel audio coding operation is performed simply based on inter-channel information regardless of the number of elements of a channel signal to be coded.